Prototypical Reasoning with Low Complexity Description Logics: Preliminary Results

We present an extension epsilon L+perpendicular to T of the description logic epsilon L+perpendicular to for reasoning about prototypical properties and inheritance with exceptions. epsilon L+perpendicular to T is obtained by adding to epsilon L+perpendicular to a typicality operator T, which is intended to select the "typical" instances of a concept. In epsilon L+perpendicular to T knowledge bases may contain inclusions of the form "T(C) is subsumed by P", expressing that typical C-members have the property P. We show that the problem of entailment in epsilon L+perpendicular to T is in CO-NP.